Daily Punch 10-12-18 Sharp Blades spell for DnD 5e

How about something to make your blades sharp in the dark?

Sharp Blades

2nd-level transmutation

Casting Time: 1 action
Range: Touch
Components: V, S
Duration: 1 hour

You touch a weapon. Until the spell ends,  your weapon attacks score a critical hit on a roll of 19 or 20.

At Higher Levels: When you cast this spell using a spell slot of 6th level or higher, your weapon attacks score a critical hit on a roll of 18 or 20.